Utilisation of Electrochemical Methods for Characterization of same Corrosion Inhibitors for Steel and Copper

The effect of chromate and molybdate on the corrosion inhibition of copper and steel has been investigated in two eutectics solution at room temperature. We used stationary electrochemical methods and optical microscopy for the characterization of these materials. For steel, the molybdate inhibitor appears less efficient than the chromate one; for copper the polarization curves present an anodic passivation domain only in the chromate inhibited medium. The possibilities of galvanic coupling between them were simulated. This simulation has shown that, between copper and steel, the risk is more important in chromate medium than in molybdate one

Ecobiophysical Aspects on Nanosilver Biogenerated from Citrus reticulata

In recent years, a considerable interest was paid to ecological strategies in management of plant diseases and plant growth. Metallic nanoparticles (MNPs) gained considerable interest as alternative to pesticides due to their interesting properties. Green synthesis of MNPs using plant extracts is very advantageous taking into account the fact that plants are easily available and eco-friendly and possess many phytocompounds that help in bioreduction of metal ions. In this research work, we phytosynthesized AgNPs from aqueous extract of Citrus reticulata peels, with high antioxidant, antibacterial, and antifungal potential. These “green” AgNPs were characterized by modern biophysical methods (absorption and FTIR spectroscopy, AFM, and zeta potential measurements). The nanobioimpact of Citrus-based AgNPs on four invasive wetland plants, Cattail (Typha latifolia), Flowering-rush (Butomus umbellatus), Duckweed (Lemna minor), and Water-pepper (Polygonum hydropiper), was studied by absorption spectroscopy, by monitoring the spectral signature of chlorophyll. The invasive plants exhibited different behavior under AgNP stress. Deep insights were obtained from experiments conducted on biomimetic membranes marked with chlorophyll a. Our results pointed out the potential use of Citrus-based AgNPs as alternative in controlling pathogens in aqueous media and in management of aquatic weeds growth

Optimal Control Based on the Polynomial Least Squares Method

In this paper an approach for computing an optimal control law based on the Polynomial Least Squares Method (PLSM) is presented. The initial optimal control problem is reformulated as a variational problem whose corresponding Euler-Lagrange equation is solved by using PLSM. A couple of examples emphasize the accuracy of the method

Polynomial Least Squares Method for Fractional Lane–Emden Equations

This paper applies the Polynomial Least Squares Method (PLSM) to the case of fractional Lane-Emden differential equations. PLSM offers an analytical approximate polynomial solution in a straightforward way. A comparison with previously obtained results proves how accurate the method is

A Comparative Study on Tribocorrosion of Two Ni-Cr Model Alloys in Solution of Boric Acid and Lithium Hydroxide

International audienceTribocorrosion of two Ni -Cr model alloys was investigated for different contact pressures in a solution of boric acid and lithium hydroxide at room temperature. The sliding tests were performed with a pin - on - disc tribometer designed to evaluate the synergistic effect between corrosion and wear. The combined corrosion -wear degradation during sliding tests was monitored and evaluated by open circuit potential measurements and electrochemical impedance spectroscopy measurements. The sliding track morphology was investigated by SEM and profilometric measurements after sliding tests. The total material loss generated by the deterioration of the protective oxide layer due to combined chemical / electrochemical and mechanical interactions in the sliding track area was assessed and compared from quantitative and qualitative point of view for these two Ni -Cr model alloys

INFLUENCE OF A COOLING LIQUID ON THE CORROSION BEHAVIOUR OF AlMn ALLOY

International audienceElectrochemical behaviour of AlMn alloys was determined by stationary electrochemical methods: potential versus time, polarization curves and linear polarization resistance recorded at different temperatures in a commercial cooling liquid, Glaceol D, which contains tolyltriazole as a corrosion inhibitor. The later was found to be an anodic corrosion inhibitor. The inhibition efficiency increases as the added concentration of the cooling liquid is increased (95% for 50%vol. Glaceol D). At the ambient temperature, the corrosion resistance of this aluminium alloy is increased with the immersion time, unfortunately at higher temperatures the corrosion rate is increased too. The intermetallic particles, such as Al-6(MnFe) and alpha-Al(Mn,Fe)Si, were found to be the cathodic sites for the corrosion of aluminium matrix

Least Squares Differential Quadrature Method for the Generalized Bagley–Torvik Fractional Differential Equation

In this paper, the least squares differential quadrature method for computing approximate analytical solutions for the generalized Bagley–Torvik fractional differential equation is presented. This new method is introduced as a straightforward and accurate method, fact proved by the examples included, containing a comparison with previous results obtained by using other methods

A Least Squares Differential Quadrature Method for a Class of Nonlinear Partial Differential Equations of Fractional Order

In this paper a new method called the least squares differential quadrature method (LSDQM) is introduced as a straightforward and efficient method to compute analytical approximate polynomial solutions for nonlinear partial differential equations with fractional time derivatives. LSDQM is a combination of the differential quadrature method and the least squares method and in this paper it is employed to find approximate solutions for a very general class of nonlinear partial differential equations, wherein the fractional derivatives are described in the Caputo sense. The paper contains a clear, step-by-step presentation of the method and a convergence theorem. In order to emphasize the accuracy of LSDQM we included two test problems previously solved by means of other, well-known methods, and observed that our solutions present not only a smaller error but also a much simpler expression. We also included a problem with no known exact solution and the solutions computed by LSDQM are in good agreement with previous ones